Where do I enter the activation key for my Office 2010 Home and Business trial?

I purchased an Office Home and Business 2010 product key card (no media). I then downloaded the Office Home and Business 2010 trial. This computer is being sent out to a user so I don't want to wait for the trial to expire then enter the code. Does anyone know where to find the button, menu option etc. so that I can enter the key/convert to full version? Can this be done?

My key card instructions tell me to click on "Microsoft Office 2010" from the start menu. No can do, no such program anywhere that I can find. I just have the usual Word, PowerPoint, Outlook etc icons in the Microsoft folder (and no activate your Office Trial applications in there either). Im running Win XP if that matters.

I spent about 15 minutes googling this and I couldn't get answer due to the fact that there are about 10,000 hits on how to cheat the activation and hack yourself a free copy